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X‐ray topographic investigation of growth defects in natural calcium fluoride crystals
Author(s) -
Desai C. C.
Publication year - 1981
Publication title -
kristall und technik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0023-4753
DOI - 10.1002/crat.19810160408
Subject(s) - dislocation , cleavage (geology) , crystallography , crystal (programming language) , materials science , x ray , optics , chemistry , physics , composite material , fracture (geology) , computer science , programming language
Calcium fluoride crystals have been cleaved along {111} faces and the freshly cleaved faces have been chemically etched in 2.6 N nitric acid solution. The etched faces have been optically studied. One‐to‐one correspondence of dislocation etch pits have been established on the matched cleavage faces and on the opposite sides of thin flakes. The same crystal has been studied using X‐ray topographic technique. By using 02 2 ‐ and 0 2 2 reflections, stereopair projection topographs were studied and compared with the optical micrographs. The close resemblance between dislocation etch pits and dislocation out‐crop images has been established. The orientation of the Burgers vectors of the dislocation lines has been identified using AgKα radiation with 11 1 ‐, 1 1 1‐ and 1 11 reflections. It has been confirmed that Burgers vectors of dislocation lines lie parallel to 〈110〉 directions. The implications are discussed.